Page 115 - PortGPT_V2.1_C8_Flipbook
P. 115
8 Introduction to
Event Handling
Let’s surf
What is Event and Event Handling Examples of Events
Onclick Event Using Functions for Event Handling
The way that JavaScript interacts with HTML is through events that happen whenever a user
or browser modifies a page. The actions of pressing any key/button, closing a window, resizing a
window, etc. are examples of events.
WHAT IS EVENT AND EVENT HANDLING
An event is defined as a change in an object's state. There are a number of events in HTML that show
when a user or browser performs a certain action. JavaScript responds to these events when JS code
is embedded in HTML and permits execution. The act of responding to events is known as event
handling. As a result, JavaScript uses event handlers to handle HTML events.
EXAMPLES OF EVENTS
There are various types of events that can occur. For example:
• On a certain element, the user performs selection, clicking, or hovering of the cursor.
• The user clicks a key on the keyboard.
• Resizing or closing the browser window.
• A web page completes loading. Tech Fact
• Submission of a form. Event handlers are also referred
• A video plays, is paused, or ended. to as event listeners.
• An error takes place
You can attach an event handler to an event to respond to it. This is a section of code that executes
when the event occurs, often a JavaScript function that you write as a programmer. We refer to
defining such a section of code to execute in response to an event as "registering an event handler."
Introduction to Event Handling 113

